1. Field of the Invention
The invention relates to a heat exchange device of modular structure, more particularly useful for exchanging heat between several fluids, particularly between two gases.
2. Description of the Prior Art
Tube-and-shell heat exchangers are known. In these devices, one of the fluids taking part in the exchange is passed through the tubes and the other one is passed around the tubes within the shell. The exchange surface per unit volume, called specific surface, which can be obtained with these exchangers is generally limited since, for construction reasons, it is difficult to reduce the diameter of the tubes and the distance between the tubes below about 1 cm.
Plate exchangers can be used to obtain more important exchange specific surfaces. In these exchangers, the fluids which take part in the exchange circulate on both sides of the different plates, but the specific surface is also limited by the necessity to not unduly reduce the distance from plate to plate.
Heat exchangers are also known, which consist of superposed perforated sheets, so juxtaposed as to form channels, by superposition of the perforations; some channels can be used to circulate a relatively hot fluid and some others a relatively cool fluid, the heat transfer between the channels being performed by conduction through the material forming at least part of the sheets.
The heat exchangers are usually made of metallic materials. When a condensation takes place in the course of the heat exchange, as, for example, when recovering heat from the fumes of boilers, these materials are liable to be easily corroded.